A growing hobbyist and professional endeavor is comprised of modifying, or "souping-up," stock automobile engines for National Hot Rod Association (NHRA) sanctioned competition racing. The modifications necessary to increase the horsepower of the engine to effectively compete increases the torque of the engine whereby further modifications are necessary to deal with the increased horsepower and torque of the engine.
Such modifications include a motor plate if mounted to the front of the engine block and is fixedly mounted to the car frame by bolting motor plate to tabs welded to the inner edges of the car frame. The motor plate assembly provides additional support to the modified engine. Otherwise the increased torque of the modified engine would separate the engine from its standard engine mounts. Also the standard engine drive pulley, which drives the water pump pulley, is replaced by a racing pulley which is strengthened to accommodate the increased engine power and torque. A common such racing pulley is the "MARCH" pulley which is used in such modified racing car engines.
In standard car engines, the drive pulley is operated by a balancer pressed onto the engine crankshaft. The balancer is placed between the drive pulley and the engine block and is weighted to provide a dampening device. A drive belt is operably attached to the drive pulley and the water pump pulley such that the respective belt grooves are vertically aligned. The drive pulley drives the water pump via the water pump pulley so that coolant water is circulated through the radiator to dissipate engine heat.
The drive pulley is attached to the balancer by three drive pulley bolts equally spaced circumferentially about the drive pulley. While the standard balancer may also be replaced by a modified, strengthened racing balancer which is of greater width, many times it is not so replaced. However, the "MARCH" racing pulley is constructed to accommodate racing balancers as described below.
The "MARCH" pulley includes a central bore which receives the balancer. Circumferentially extending flanges concentric with the central bore are one of which is adjacent the central bore provided which are in turn received by corresponding circumferentially extending grooves in the racing balancer. The "MARCH" pulley, standard balancer, and racing balancer each include three corresponding drive pulley bolts holes equally spaced circumferentially outward of the circumferentially extending flange which are aligned upon assembly to allow receipt of three respective drive pulley bolts to operably connect the "MARCH" pulley to either the standard balancer or the racing balancer.
The motor plate is of a roughly triangular configuration and is mounted to the front of the engine block with its apex at the top. It includes a mid-point cut-out area at its lower edge to accommodate the engine's balancer drive shaft and standard balancer. The engine's water pump is then bolted to the motor plate and thus is spaced a distance equal to the thickness of the motor plate from the engine block. The motor plate cut-out fits around the balancer drive shaft and standard balancer so that the "MARCH" pulley remains in its original position relative to the engine block such that the respective belt grooves of the "MARCH" pulley and water pump pulley are no longer in alignment.
To realign the belt grooves for efficient operation of the water pump, a group of smooth faced, circular spacers with central bores to accommodate the balancer are inserted between the "MARCH" pulley and the standard balancer. These spacers also include bolt holes to accommodate the drive pulley bolts.
Although the spacers allow for realignment of the "MARCH" pulley belt groove and the water pump pulley belt groove, the drive pulley bolts shear or break at relatively frequent intervals requiring their replacement which results in increased maintenance and cost as well as depriving the engine of coolant water since the "MARCH" pulley decreases or ceases rotation and thus no longer or inadequately drives the water pump pulley and water pump. During competitive races, such delays may cause a forfeit or engine damage at worst and major inconvenience at best while at least the drive pulley bolts are replaced.
It has been discovered that the increased torque of the modified engine is directed almost exclusively at the racing pulley bolts in the prior art method of using smooth faced spacers to space the "MARCH" pulley from the standard balancer which results in the high incidence of racing pulley bolt failures.
It is an object of the present invention to provide a pulley spacer which eliminates drive pulley bolt failure and subsequent loss of drive pulley.